I don't know if there is a wrong kind of wood for hügelkultur, but the older the wood the better it seems to act like a sponge.
- Avoid wood from allelopathic trees like black walnut (for its juglone toxicity); high-resin trees like pine, spruce, yew, juniper and cedar; and hard, rot-resistant woods such as black locust, Osage orange and redwood. Any type of wood with sprouting potential (such as willow) should be completely dead before using.